Camera having a liquid crystal display device

ABSTRACT

A liquid crystal display panel in which a signal electrode provided on a first substrate ( 1 ), a counter electrode provided on a second substrate ( 2 ), and a liquid crystal layer ( 18 ) between the substrates, and which carries out display without polarizers by changing the degree of transmission and scattering by means of a voltage applied to a pixel part. A light source part ( 27 ) is provided along the periphery of both substrates ( 1, 2 ), and a polarization separating device ( 30 ) is provided between the liquid crystal panel and the light source part ( 27 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device and,more specifically, to a liquid crystal display device in which almostthe entire display area is brought into a transparent state for acondition behind it to be clearly viewed, so that only a specificpattern isolated in the display area is displayed in a scattering state.

Further, the invention specifically relates to a liquid crystal displaydevice which is installed in a finder optical system of a camera to besuitable for displaying a target pattern for autofocus in a findervisual field.

2. Description of the Related Art

A liquid crystal display device using a liquid crystal display panel(LCD) has an advantage of thin-profile, light weight and, additionally,an extremely low power consumption, and thus it has been used asdisplays of wide-ranging devices including various kinds of portableelectronic devices such as electronic calculators, cellular phones,wristwatches, cameras, video cameras, notebook personal computers, andthe like.

In the liquid crystal display panel, a pair of transparent substratesare coupled together with a fixed gap provided therebetween with asealing part provided around a display area, and the gap is filled witha liquid crystal layer to constitute a liquid crystal cell. Then,voltage is partially applied to the liquid crystal layer by a signalelectrode and a counter electrode which are provided on opposed innersurfaces of the two substrates, thereby making it possible to change itsoptical characteristics (twist of a polarization axis, birefringenceproperty, transmission/scattering, and the like).

Therefore, transmission/absorption or scattering of light, hue, and thelike are different between a part where voltage is applied to the liquidcrystal layer and a part with no voltage by combination with polarizersdisposed on both sides of the liquid crystal cell or the liquid crystalcell itself, whereby various kinds of displays can be performed.

In such liquid crystal display devices, there are a transmission typeand a reflection type or a reflection type with illumination. Thetransmission type liquid crystal display device has a light source partbelow the first substrate which is opposite to the visible side of theliquid crystal display panel. The reflection type liquid crystal displaydevice has a light source part above the second substrate on the visibleside of the liquid crystal display panel, or external light is incidentthereon from the visible side.

In the case of the reflection type liquid crystal display device withillumination, a display, during a reflection display, is performed usinga difference in strength of light which is made incident on the liquidcrystal layer from the second substrate side and reflected from theliquid crystal layer side to go out again to the visible side, and adisplay similar to the transmission type liquid crystal display deviceis performed during a transmission display by turning on the lightsource part below the first substrate.

Further, in a liquid crystal display panel having a liquid crystal layercomposed of a twisted nematic (TN) liquid crystal or a super twistednematic (STN) liquid crystal sandwiched between the pair of transparentsubstrates, it is necessary to dispose polarizers on both sides thereof,which decreases the transmittance of light, resulting in a darktransmission display.

Accordingly, for example, when the liquid crystal display panel is usedas a finder part of a camera, its finder visual field becomes dark inthe case such liquid crystal display panel with polarizers is used,because of absorption by the polarizers.

Furthermore, when the environment where the camera is used is dark, thedisplay of the target pattern or the like on the liquid crystal displaypanel cannot be viewed. If a light source part is therefore disposed onthe first substrate side which is opposite to the visible side forillumination, the light from the light source part becomes noise tolight from a photographing lens because light from a subject is incidentthrough the photographing lens which is provided on the first substrateside, presenting a problem that the subject becomes difficult to berecognized by the observer.

The present invention is made to solve these problems, and its object isto bring almost the entire display area into a transmission state withhigh transparency without using a polarizer in the liquid crystaldisplay panel, and to display only a specific pattern in the displayarea always clearly even when the background is bright or dark and toprevent the background from being hard to view.

SUMMARY OF THE INVENTION

A liquid crystal display device according to the present invention is aliquid crystal display device including a liquid crystal display panelin which a first substrate formed with a signal electrode and a secondsubstrate formed with a counter electrode formed on one surface,respectively, are bonded together, with the signal electrode and thecounter electrode opposed to each other, with a fixed gap therebetweenprovided by interposing a sealing part at an outer peripheral part of adisplay area, and a liquid crystal layer is provided in the gap, and ischaracterized by being structured as follows in order to achieve theabove-described objects.

The signal electrode is composed of a surrounding electrode formed overalmost the entire area of the display area, a pattern electrodeisolatedly formed within the surrounding electrode, and a wiringelectrode formed across the surrounding electrode with a gap providedbetween the wiring electrode and the surrounding electrode in order toselectively apply voltage to the pattern electrode.

Further, the counter electrode is provided over the entire area of thedisplay area to face the signal electrode.

Furthermore, the first substrate and the second substrate and the signalelectrode and the counter electrode are all transparent, and the liquidcrystal layer is a scattering type liquid crystal layer which changes intransmittance and scattering rate depending on existence or absence ofapplication of voltage by means of the signal electrode and the counterelectrode, in which transparency increases in a part to which voltage isapplied.

Moreover, a light source means which emits linearly polarized light isdisposed outside a peripheral part of the liquid crystal display panel,and at least a part of the sealing part facing the light source meanshas a light transmitting property to allow linearly polarized lightemitted from the light source means to pass through the sealing part andenter the liquid crystal layer.

Alternatively, it is also preferable that the signal electrode iscomposed of a pattern electrode isolatedly formed within the displayarea, and a wiring electrode formed across the display area in order toselectively apply voltage to the pattern electrode, and the counterelectrode is provided only in an area to face the pattern electrode.

The liquid crystal layer in this case is a scattering type liquidcrystal layer which changes in transmittance and scattering ratedepending on existence or absence of application of voltage by means ofthe signal electrode and the counter electrode, in which a scatteringdegree increases in a part to which voltage is applied. The otherstructure may be the same as that of the above-described liquid crystaldisplay device.

In these liquid crystal display devices, the liquid crystal displaypanel, in which an outside of the second substrate is a visible side,always presents a condition outside the first substrate to the visibleside.

Further, it is preferable that a luminosity of a scattering part of theliquid crystal layer becomes higher than luminosities of other partswhile a light source part of the light source means is turned on, andthe luminosity of the scattering part of the liquid crystal layerbecomes lower than the luminosities of the other parts while the lightsource part is turned off.

Furthermore, it is possible that the light source means is composed of alight source part and a polarization separating device disposed betweenthe light source part and an outer peripheral part of the liquid crystaldisplay panel.

It is more desirable that an optical means composed of a convex lens ora diffuser is provided between the light source part and thepolarization separating device in the light source means.

In this case, it is most preferable that the scattering type liquidcrystal layer of the liquid crystal display panel is a mixed liquidcrystal layer composed of transparent solid substances and liquidcrystal, which is produced by applying ultraviolet light to liquidcomposed of the liquid crystal and organic monomers, and thepolarization separating device is disposed so that a transmission axisthereof almost matches with a direction in which a difference between arefractive index of the transparent solid substance and a refractiveindex of the liquid crystal of the mixed liquid crystal layer is small.

The scattering type liquid crystal layer may also be a mixed liquidcrystal layer composed of transparent solid substances having alignmentproperties and liquid crystal, which is produced by applying ultravioletlight to liquid made by mixing liquid crystal polymers into the liquidcrystal and organic monomers.

As the polarization separating device, an absorption type polarizerhaving a transmission axis and an absorption axis substantiallyperpendicular to the transmission axis, or a reflection type polarizerhaving a transmission axis and a reflection axis substantiallyperpendicular to the transmission axis can be used.

When the polarization separating device is a reflection type polarizer,it is preferable that a diffuser is provided between the polarizationseparating device and the light source part, and a reflector is providedaround the light source part.

It is also preferable that, as the polarization separating device, theabsorption type polarizer is disposed on the liquid crystal displaypanel side and the reflection type polarizer is disposed on the lightsource side respectively with directions of the transmission axes of theabsorption type polarizer and the reflection type polarizer matchingwith each other.

Further, it is preferable that light intensity change means whichcontrols increase and decrease of an intensity of light to make incidenton the liquid crystal display panel in accordance with an intensity oflight incident on the liquid crystal display panel from outside thefirst substrate is provided in the light source means. The lightintensity change means may manually or automatically control voltage orelectric current applied to the light source part to change its lightemission strength or light emission period.

It is also possible that the light intensity change means is composed ofa liquid crystal cell provided between the polarization separatingdevice and the light source part, a polarizer arranged on a light sourcepart side of the liquid crystal cell, an exposure meter for detectingthe intensity of the light incident from outside the first substrate,and a liquid crystal driving circuit for changing voltage applied to theliquid crystal cell in accordance with an output from the exposuremeter, so that a transmittance of the liquid crystal shutter composed ofthe liquid crystal cell, and the polarization separating device and thepolarizer on either side of the liquid crystal cell is controlled tochange the intensity of the light to make incident on the liquid crystaldisplay panel.

It is desirable that an ultraviolet cutting layer is provided at leaston one of outer surfaces of the first and second substrates of theliquid crystal display panel.

It is preferable that an anti-reflection layer for preventing reflectionof light within a wavelength range of light emitted by the light sourcepart is provided on outer surfaces of at least one of the first andsecond substrates of the liquid crystal display panel.

The light source part preferably emits light with an optical wavelengthin a range from 380 nanometers (nm) to 800 nanometers (nm). Further, aplurality of light source parts are arranged outside the peripheral partof the liquid crystal display panel, thereby obtaining more sufficientintensity of light. It is also possible that, as the plurality of lightsource parts, light source parts for emitting light in differentwavelength regions (emitted light colors) are provided, or a pluralityof light emitting elements for emitting light in different wavelengthregions are provided in one light source part. They may be selectivelyused.

It is possible that the liquid crystal display device in theexplanations is constituted as a module to be installed in a finderoptical system of a camera, and the pattern electrode of the liquidcrystal display panel is an electrode for displaying an autofocus targetpattern.

In this case, it is preferable that a finder screen is disposed outsidethe first substrate and a finder lens is disposed outside the secondsubstrate of the liquid crystal display panel respectively.

In the liquid crystal display device according to the invention, almostthe entire display area of the liquid crystal display panel can bebrought into the transmission state for a condition behind the firstsubstrate to be always viewed clearly. The employment of the scatteringtype liquid crystal layer as the liquid crystal layer enables a displaywithout using a polarizer, so that the transmittance of the liquidcrystal display panel is improved to enhance the visibility of thebackground. Further, it is possible that only a part of the liquidcrystal layer sandwiched between the pattern electrode and the counterelectrode is brought into the scattering state, so that when thebackground is bright, a dark pattern is displayed therein, and when thebackground is dark, a bright pattern is displayed by turning on thelight source part. In this event, the collimate lens is provided betweenthe outer peripheral part of the liquid crystal display panel and thelight source part to make the light from the light source part a rayparallel to the first substrate and the second substrate of the liquidcrystal display panel and to let it enter the liquid crystal layer,whereby the light scattered or reflected in the transparent part of theliquid crystal layer to go out to the visible side decreases, so thatonly the pattern in the scattering part is displayed bright withoutdifficulty in viewing the background.

The polarization separating device is provided between the outerperipheral part of the liquid crystal display panel and the light sourcepart, the scattering type liquid crystal layer of the liquid crystaldisplay panel is the mixed liquid crystal layer composed of thetransparent solid substances and the liquid crystal, which is producedby applying ultraviolet light to the liquid composed of the liquidcrystal and the organic monomers, and the polarization separating deviceis disposed so that the transmission axis thereof almost matches withthe direction in which the difference between the refractive index ofthe transparent solid substance and the refractive index of the liquidcrystal of the mixed liquid crystal layer is small. Thereby, the lightfrom the light source part passes through the polarization separatingdevice to be linearly polarized, and the direction of the polarizedlight is in the direction in which the difference in refractive indexbetween the transparent solid substance and the liquid crystal is small,so that the incident light from the light source part passes through,without scattered, the transmission part of the liquid crystal layer andis scattered only in the scattering part to realize a display of abright pattern.

Almost the entire liquid crystal display panel other than the patterndisplay part is brought into the transparent state, whereby the incidentlight from the light source part (side light) disposed around the liquidcrystal display panel can be introduced to the entire display areathrough use of the reflection due to the difference in refractive indexbetween the first substrate and the air layer, and the reflection due tothe difference in refractive index between the second substrate and theair layer.

Further, the intensity of light of the light source part which reachesthe liquid crystal display panel decreases in the case where thepolarization separating device is simply disposed between the liquidcrystal display panel and the light source part as compared to the casewhere the polarization separating device is not provided. Therefore, thereflection type polarizer is used as the polarization separating deviceto emit a linearly polarized light to the liquid crystal layer, and thecomponent reflected toward the light source part is returned again tothe reflection type polarizer, by cancelling its polarization andreflecting by the reflector, thereby improving the efficiency ofemitting light.

When the strength of the light incident from outside the first substrateconstituting the liquid crystal display panel is low, the light from thelight source part (side light) provided around the liquid crystaldisplay panel is slightly reflected toward the observer from thetransparent part of the liquid crystal display panel to interfere thevisibility of the back of the first substrate, and thus it is better todecrease the intensity of the light (brightness) from the light sourcepart by the light intensity change means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view showing a first embodiment of a liquid crystaldisplay device according to the invention;

FIG. 2 is a schematic cross-sectional view taken along a line 2—2 inFIG. 1;

FIG. 3 is a plane view of a first substrate formed with a signalelectrode on the upper surface in FIG. 1;

FIG. 4 is a plane view of a sealing part provided between the firstsubstrate and a second substrate in FIG. 1;

FIG. 5 is a plane view of the second substrate formed with a counterelectrode on the lower surface in FIG. 1;

FIG. 6 is a plane view of a camera module in which the liquid crystaldisplay device of the first embodiment is installed;

FIG. 7 is a schematic cross-sectional view taken along a line 7—7 inFIG. 6;

FIG. 8 is a chart showing characteristics of the liquid crystal displaydevice according to the invention;

FIG. 9 is an explanatory view for explaining the display principle ofthe liquid crystal display device according to the first embodiment ofthe invention;

FIG. 10 is a schematic cross-sectional view, similar to FIG. 7, of acamera module showing a second embodiment of the liquid crystal displaydevice according to the invention;

FIG. 11 is an explanatory view for explaining the display principle ofthe liquid crystal display device according to the second embodiment ofthe invention;

FIG. 12 is a schematic cross-sectional view, similar to FIG. 7, of acamera module showing a third embodiment of the liquid crystal displaydevice according to the invention;

FIG. 13 is a block diagram showing one example of light intensity changemeans thereof;

FIG. 14 is a side view showing a state in which the camera module thatis the embodiment of the liquid crystal display device according to theinvention is installed in a camera, viewing through a camera body; and

FIG. 15 is a front view showing the same without its photographing lens.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be explained with reference tothe accompanying drawings.

First embodiment: FIG. 1 to FIG. 9

First, the first embodiment of a liquid crystal display device accordingto the invention is explained with reference to FIG. 1 to FIG. 9.

FIG. 1 is a plane view of a liquid crystal display panel and a lightsource part of the liquid crystal display device, FIG. 2 is a schematiccross-sectional view taken along a line 2—2 in FIG. 1, FIG. 3 is a planeview of a first substrate formed with a signal electrode on the uppersurface thereof, FIG. 4 is a plane view of a sealing part providedbetween the first substrate and a second substrate, and FIG. 5 is aplane view of the second substrate formed with a counter electrode onthe lower surface thereof.

With these drawings, the structure of the liquid crystal display panelof this embodiment is explained first.

In a liquid crystal display panel 6, as shown in FIG. 1 and FIG. 2, afirst substrate 1 formed with a signal electrode 20 and a secondsubstrate 2 formed with a counter electrode 21 on one surface,respectively, are coupled together, with the signal electrode 20 and thecounter electrode 21 opposed to each other, with a fixed gaptherebetween provided by interposing a sealing part 3 at the outerperipheral part of a display area, and the gap is filled with a liquidcrystal layer 18.

The signal electrode 20 is composed of a surrounding electrode 11 formedover almost the whole display area on the inner surface of the firstsubstrate 1, target electrodes 5 a, 5 b and 5 c which are patternelectrodes isolatedly formed within the surrounding electrode 11, andwiring electrodes 8 a, 8 b and 8 c which are formed across thesurrounding electrode 11 with gaps G1 (FIG. 2) provided between they andthe surrounding electrode 11 in order to selectively apply voltage toeach of the target electrodes.

The counter electrode 21 is provided over the whole display area on theinner surface of the second substrate 2 to face the signal electrode 20.

The first substrate is a transparent glass substrate and provided, onits one surface (upper surface in the drawing), with the surroundingelectrode 11 formed over almost the whole display area, the three targetelectrodes 5 a, 5 b and 5 c isolatedly formed within the surroundingelectrode 11 to form target pattern forms for automatic focus(autofocus), and the wiring electrodes 8 a, 8 b and 8 c connected to therespective target electrodes 5 a, 5 b and 5 c, as the signal electrode20 made of an indium tin oxide (ITO) film that is a transparentconductive film as shown in FIG. 3.

In the vicinity of one side on the first substrate, three connectingelectrodes 12, 13 and 14 for the target electrodes and a connectingelectrode 15 for the surrounding electrode are provided in a row.Further, a connecting electrode 24 for the counter electrode on thesecond substrate is also provided. These connecting electrodes are allalso made of the same ITO film as that of the signal electrode 20.

The three target electrodes 5 a, 5 b and 5 c are connected to therespective connecting electrodes 12, 13 and 14 by the wiring electrodes8 a, 8 b, and 8 c crossing the surrounding electrode 11 respectively,and the surrounding electrode 11, is connected to the connectingelectrode 15 for the surrounding electrode by a surrounding electrodewiring electrode 16.

Between each of the target electrodes 5 a, 5 b and 5 c and wiringelectrodes 8 a, 8 b and 8 c, and, the surrounding electrode 11, the gapG1 is respectively provided as shown in FIG. 2. This gap is preferablymade about 3 micrometers (μm) because the smaller the gap, the moreinconspicuous and the better. The wiring electrodes 8 a, 8 b and 8 c arepreferably also made to have a width of about 3 μm so as to beinconspicuous.

Further, the second substrate 2 which is opposed to the first substrate1 with a gap of 7 micrometers (μm) to 10 micrometers (μm) is also atransparent glass substrate, and is provided, on its one surface (lowersurface in the drawing), with the counter electrode 21 made of an ITOfilm over the entire surface of the display area as shown in FIG. 5.This counter electrode 21 is also formed with a wiring electrode 23.

To oppose the first substrate 1 and the second substrate 2 with thefixed gap provided therebetween, spacers, not shown, made of plastic areinterposed in the gap, and the substrates are coupled together as shownin FIG. 2 by the sealing part 3, which is composed of a transparentsealing material provided at the outer peripheral part of the displayarea, as clearly shown in FIG. 4.

This makes each of the target electrodes 5 a, 5 b and 5 c, and thesurrounding electrode 11 on the first substrate 1, and, the counterelectrode 21 on the second substrate 2 oppose each other with apredetermined gap therebetween.

A closing part 25 is provided at a part of the sealing part 3, andliquid crystal is introduced through this closing part 25 and closedwith a closing material 26, thereby filling the gap between the firstsubstrate 1 and the second substrate 2 with the liquid crystal layer 18.

This makes each of the target electrodes 5 a, 5 b and 5 c (only thetarget electrode 5 c is shown in FIG. 2) and the surrounding electrode11 on the first substrate 1, and, the counter electrode 21 on the secondsubstrate 2 oppose each other with the liquid crystal layer 18sandwiched therebetween.

To enable connection of the counter electrode 21 to an external circuit(not shown), its wiring electrode 23 is electrically connected to thecounter electrode connecting electrode 24 provided on the firstsubstrate 1 by an anisotropic conductive sealing material 22 made bymixing conductive particles in an adhesive.

The liquid crystal layer 18 is a mixed liquid crystal layer made byinjecting a precursor of a mixed liquid crystal containing organicmonomers in a liquid crystal into the gap between the first substrate 1and the second substrate 2 through the end-closing part 25 of the outerperipheral sealing part 3, closing it with the closing material 26, andthen applying ultraviolet light thereto from the outside to make theorganic monomers to organic polymers to thereby disperse transparentsolid substances in the liquid crystal.

The liquid crystal layer 18 composed of the mixed liquid crystal layeris a scattering type liquid crystal layer whose transmittance andscattering rate change depending on existence or absence of applicationof voltage by means of the signal electrode 20 and the counter electrode21, in which the transparency (transmittance) increases in a part towhich voltage is applied.

The overlap between the target electrode 5 (hereinafter, 5 a, 5 b and 5c are all referred to as 5 without distinction) and the counterelectrode 21 of this liquid crystal display panel 6 constitutes a pixelpart forming a display pattern, and by applying voltage between thetarget electrodes 5 and the surrounding electrode 11, and, the counterelectrode 21, directions of liquid crystal molecules are aligned with adirection of an electric field in the whole area of the liquid crystallayer 18 to increase the transmittance, which can bring almost theentire display area into a transparent state.

Further, the voltage applied to the target electrodes 5 is turned off tobring parts of the liquid crystal layer 18 on the target electrodes 5into a scattering state, thereby displaying target patterns.

In this case, parts of the liquid crystal layer 18 facing the wiringelectrodes 8 a, 8 b and 8 c, and the gaps between them and thesurrounding electrode 11 are also brought into a scattering state, butthey are hardly recognized in the state because widths of the gap G1 andthe wiring electrodes 8 a, 8 b, and 8 c are small, 3 micrometers (μm),respectively.

The employment of the above-described structure makes it possible tobring only the part of the liquid crystal layer 18 facing the targetelectrode 5 into the scattering state to display the target pattern.

FIG. 6 is a plane view of a camera module in which this liquid crystaldisplay device is installed, showing a state in which only an autofocustarget pattern 9 produced by the center target electrode 5 among thethree target electrodes is displayed within a display frame 37 togetherwith a background (subject) image which is recognized in a transparentdisplay area. FIG. 7 is a schematic cross-sectional view taken along aline 7—7 in FIG. 6. Incidentally, in FIG. 7, the target electrode 5 isshown not as a pair of small electrodes but as one relatively largeelectrode for convenience of explanation.

A large voltage is applied between other target electrodes 5 and thesurrounding electrode 11, and, the counter electrode 21 to make a statein which only the center target pattern 9 can be recognized. In thisstate, the focus can be adjusted in the center target pattern 9.

As shown in these drawings, the liquid crystal display panel 6 is set ina panel holding frame 31, and the connecting electrodes 12, 13, 14, 15and 24 on the first substrate 1 are electrically connected to respectivewires of a flexible print circuit board (FPC) 36 through a zebra rubberconnector 32. To position the FPC 36, a positioning pin 33 is providedon the panel holding frame 31.

Further, to establish connection between the zebra rubber connector 32and the FPC 36, a panel fixing frame 38 is provided. The panel fixingframe 38 is provided with the display window 37 at a part correspondingto the display area of the liquid crystal display panel.

Furthermore, to prevent the liquid crystal display panel from a rapidchange in temperature due to a change in environment, a heat insulatingseal 39 made of a silicon resin is filled in a gap between the panelholding frame 31 and the panel fixing frame 38. The heat insulating seal39 also fixes the panel holding frame 31 and the panel fixing frame 38.

Further, when light from the subject is dim, it is difficult for anobserver to recognize the target pattern 9. Therefore, a light sourcepart (side light) 27 composed of a light emitting diode (LED) device foremitting red light is provided outside the periphery of the liquidcrystal display panel 6 (at the light-band side in this embodiment).

The light source part 27 is provided with a light source part electrode28 for applying a predetermined signal to the light source part 27.Further, the light source part 27 is fixed to the panel holding frame 31by a light source part holding part 34.

Moreover, between the light source part 27 and the liquid crystaldisplay panel, a polarization separating device 30 shown in FIG. 1 andFIG. 2 is provided. Furthermore, optical means 29, whose illustration isomitted in FIG. 1 and FIG. 2, for letting the light of the light sourcepart 27 uniformly enter the entire surface of the liquid crystal displaypanel 6 is provided between the polarization separating device 30 andthe light source part 27. The optical means 29 is a convex lens(functioning as a collimator lens) whose one side facing the liquidcrystal display panel forms a convex spherical surface, or a diffuser.In FIG. 7, it is shown as a diffuser.

As the polarization separating device 30, an absorption type polarizeris employed which has a transmission axis and an absorption axissubstantially perpendicular to the transmission axis as polarizationaxes.

A ray emitted from the light source part 27 is finally made a linearlypolarized light by the polarization separating device 30 to enter theliquid crystal layer 18 of the liquid crystal display panel 6. In orderto propagate the light to the liquid crystal layer 18 without, as muchas possible, cancellation of polarization, at least a part of thesealing part 3 of the liquid crystal display panel, on which the lightfrom the light source part 27 is incident, is preferably made of atransparent sealing material having no scattering property.

With the above-described structure, the light from the light source part27 is made light at a predetermined angle by the optical means 29 asshown in FIG. 7 to enter the polarization separating device 30.

The light is made a linearly polarized light by the polarizationseparating device 30 to be emitted toward the first substrate 1, thesecond substrate 2, and the liquid crystal layer 18 which constitute theliquid crystal display panel. The light is repeatedly reflected by theinner surfaces of the first substrate 1 and the second substrate 2 dueto a difference in refractive index between the first substrate 1 andthe second substrate 2, and, an air layer (not shown) to be allowed toenter the entire liquid crystal layer 18 of the a liquid crystal displaypanel 6.

An incident light 53 from the light source part 27 shown in FIG. 7 isillustrated representing light components which are incident from thepolarization separating device 30 directly on the liquid crystal layer18. The liquid crystal layer 18 is in the transparent state in a part ofthe liquid crystal layer 18 other than the part (target part) on thetarget electrode 5 to which voltage is not applied, and thus the lightpasses, without scattered, through the former part to hardly go outtoward the observer.

The liquid crystal layer 18 is scattered on the target electrode 5 towhich voltage is not applied, which makes it possible to emit ascattered light 55 in various directions as shown in FIG. 7 and to emitit toward the observer. The scattered light 55 in FIG. 7 is shownrepresenting the scattered light toward the observer.

As for incident light from behind the first substrate 1 of the liquidcrystal display panel, an incident light 51 goes out to the visible sideas it is in a part where the liquid crystal layer 18 is not in thescattering state (in the transparent state). An incident light 52 intothe part on the target electrode 5 where the liquid crystal layer 18 isscattered is scattered by the liquid crystal layer 18 to go out to thevisible side.

More specifically, among the subject incident light 51 and the subjectincident light 52 from below (lens side of) the first substrate 1, thesubject incident light 52 is scattered by the liquid crystal layer 18 onthe target electrode 5 and thus recognized as dark by the observer, andthe subject incident light 51 is recognized as bright because the liquidcrystal layer 18 is substantially transparent.

Therefore, it becomes possible to display the target pattern dark in apicture of a bright subject. In this case, there is no layer forabsorbing light such as a polarizer in a direction of the subjectincident lights 51 and 52, so that the observer can recognize the brightsubject.

The brightnesses of the target part (part corresponding to the targetelectrode 5) in the scattering state and the background part (partcorresponding to the surrounding electrode 11) in the transmission statewhen the light source part 27 is turned on, which the observerrecognizes, are explained using FIG. 8. The horizontal axis in FIG. 8indicates the position in the display area of the liquid crystal displaypanel, and the vertical axis indicates the brightness.

Since the polarization separating device 30 is provided between thelight source part 27 and the liquid crystal display panel 6 in the firstembodiment of the invention, the brightnesses of the background partwhere the liquid crystal layer 18 is in the transparent state and thetarget part where voltage is applied to the target electrode 5 are at anextremely low level L0 as shown by solid lines 61 and 63 because of onlya very low scattering property.

In contrast to this, the brightness of the target part where voltage isnot applied to the target electrode 5 and thus the liquid crystal layer18 is in the scattering state is at a high level Lm as shown by a solidline 64 because of its scattering property. Since the subject can not berecognized at the background part which is brighter than the light fromthe subject, it is preferable that the brightness level L0 at thebackground part is as low as possible and the brightness level Lm at thetarget part is moderately high.

Therefore, it is preferable to provide a light intensity change functionfor changing the intensity of light of the light source part 27 inaccordance with the environment where the liquid crystal display deviceis used. In this embodiment, electric power applied to the light sourcepart 27 is changed manually or automatically in accordance with theintensity of light incident from behind the first substrate 1 of theliquid crystal display panel, thereby changing the intensity ofirradiation light thereof. The brightness L1 and broken lines 62 and 65shown in FIG. 8 will be used for the explanation of a second embodiment.

Next, the effectiveness of the invention is explained using FIG. 9.

The liquid crystal layer 18 is composed of schematically bar-shapedliquid crystal molecules 80 and transparent solid substances 84 eachhaving a schematically porous body made of an acrylic resin existingaround the liquid crystal molecules 80. Further, the transparent part isdesignated by 18 a, and the scattering part (target part) is designatedby 18 b.

The liquid crystal molecule 80 has a refractive index ne (its directionis assumed to be 81) corresponding to extraordinary light, and arefractive index no (its direction is assumed to be 82) corresponding toordinary light. The transparent state and the scattering state of theliquid crystal layer (mixed liquid crystal layer) 18 are generated by adifferential between a refractive index np of the transparent solidsubstance 84 and the refractive index no or ne of the liquid crystalmolecule 80, and alignment properties of the liquid crystal molecules(directions and ununiformity of the liquid crystal molecules 80).

In this embodiment, PNM-157 mixed liquid crystal manufactured byDainippon Ink and Chemicals, Inc. is used as a raw material of theliquid crystal layer 18. The gap between the first and second substratesis filled with the mixed liquid crystal, and then the mixed liquidcrystal is irradiated with ultraviolet light having a wavelength of 360nanometers (nm) or longer for 60 seconds at a strength of 30 mW/cm² toproduce a mixed liquid crystal layer composed of the transparent solidsubstances 84 and the liquid crystal molecules 80. As for the refractiveindices of the liquid crystal layer 18, no=1.5 and ne=1.7, and therefractive index np of the transparent solid substance 84 is about 1.5.Accordingly, np≈no.

When the applied voltage is small, the liquid crystal molecules 80 pointin various directions with respect to the transparent solid substances84 because of a small compelling force on the directions of the liquidcrystal molecules 80. More specifically, the liquid crystal molecules 80are arranged at random because of low alignment properties to generateinterface reflection between ne of the liquid crystal molecule and np ofthe transparent solid substance to the incident light. Therefore, aplurality of micro interface reflections are generated between theliquid crystal molecules 80 and the transparent solid substances 84,resulting in the scattering state. Accordingly, the subject incidentlight 52 is scattered to be a weak outgoing light toward the observer.

When the applied voltage is large, the long axes (directions 81 of ne)of the liquid crystal molecules 80 point in a direction from the firstsubstrate 1 to the second substrate 2 because a compelling force with astrong electric field is exerted on the directions of the liquid crystalmolecules 80.

Since the incident light from the first substrate 1 side is a circularlypolarized light in a direction parallel to the direction of therefractive index no of the liquid crystal molecule 80 (the direction inwhich the refractive index of the liquid crystal molecule 80 is no), thedifference in refractive index at the interface between the transparentsolid substance 84 and the liquid crystal molecule 80 is small, and thusthe interface reflection is hardly generated, resulting in thetransmission state. Therefore, the subject incident light 51 is hardlyscattered to be emitted with an original strength of the subjectincident light 51 toward the observer.

In FIG. 9, the figure is illustrated assuming that the front-reardirection is an X-axis 71, the vertical direction is a Y-axis 72, andthe horizontal direction is a Z-axis 73 with respect to the papersurface. However, the X-axis is difficult to recognize in the verticaldirection with respect to the paper surface, and thus it is shown by anarrow having an angle of 45°.

The emitted light 53 from the light source part 27 is a circularlypolarized light 75 with little polarization. The representativecomponents of the circularly polarized light 75 are assumed to be anX-axis direction polarized light component (first polarized lightcomponent) 76 and a Y-axis direction polarized light component (secondpolarized light component) 77. The polarization separating device 30 hasa transmission axis in the X-axis direction and an absorption axis inthe Y-axis direction. Therefore, the emitted light from the polarizationseparating device 30 becomes a linearly polarized light 78 in the X-axisdirection.

In the transparent part 18 a of the liquid crystal layer 18, the liquidcrystal molecule 80 has the refractive index ne in the direction fromthe first substrate toward the second substrate and the refractive indexno in a direction perpendicular to ne. Accordingly, when a polarizedlight parallel to the direction of the refractive index no is madeincident, reflection on the interface between the transparent solidsubstance 84 and the liquid crystal molecule 80 is hardly generatedbecause of a small difference between the refractive index no and therefractive index np of the transparent solid substance 84, which hardlygenerates scattering.

Further, in the scattering part 18 b, since the liquid crystal molecules80 point in random directions, the linearly polarized light 78 is alsoscattered to become the scattered light 55 and goes out to the visibleside, which the observer can recognize.

In other words, the polarization separating device 30 is preferablydisposed so that its transmission axis is in the direction (X-axisdirection) parallel to the direction of the refractive index no of theliquid crystal molecule 80.

With the above-described arrangement, the emitted light from thepolarization separating device 30 is hardly scattered in the transparentpart (background part) 18 a of the liquid crystal layer 18 and isscattered only in the target part of the scattering part 18 b to berecognized by the observer, which makes it possible for the observer torecognize the subject incident light 51.

Second embodiment: FIG. 10, FIG. 11 and FIG. 8

Next, the second embodiment of the liquid crystal display deviceaccording to the invention is explained with reference to FIG. 10, FIG.11 and FIG. 8.

FIG. 10 is a schematic cross-sectional view, similar to FIG. 7, of acamera module in which the liquid crystal display device is installed,in which the same portions as those in FIG. 7 are assigned the samenumerals and the explanation thereof is omitted.

On a first transparent substrate 1, an isolated target electrode 5 fordisplaying an autofocus target pattern and a wiring electrode 8 forapplying voltage thereto are provided as a signal electrode made of anindium tin oxide (ITO) film that is a transparent conductive film. Theshapes and arrangement thereof are the same as those of the firstembodiment but no surrounding electrode 11 is provided.

Further, on a second substrate 2 which is opposed to the first substrate1 with a distance of 10 micrometers (μm) provided therebetween, acounter electrode 21′ is provided only in an area opposed to the targetpattern 5 on the first substrate 1, and its wiring electrode 23′ isprovided not to cross the wiring electrode 8 of the target electrode 5.The counter electrode 21′ is connected to a counter electrode connectingelectrode (not shown) provided on the first substrate 1 by an anisotropyconductive sealing material made by mixing conductive particles in anadhesive in order to enable connection to an external circuit (notshown).

The counter electrode 21′ has almost the same area as that of the targetelectrode 5 on the first substrate 1, and further is connected to thecounter electrode connecting electrode by carrying out wiring using aposition different from that of the wiring electrode 8 on the firstsubstrate 1. This is because if this wiring crosses the wiring electrode8 of the target electrode 5 in a plane view, voltage is applied to aliquid crystal layer 18 at a part other than the target part.

The liquid crystal layer 18 used in this embodiment is made by injectinga precursor of a mixed liquid crystal layer containing organic monomersin a liquid crystal, and then applying ultraviolet light thereto toconvert the organic monomers into organic polymers, thereby formingtransparent solid substances in the liquid crystal to form the mixedliquid crystal layer 18. The organic monomers are mixed with liquidcrystal polymers to form transparent solid substances having alignmentproperties by application of ultraviolet light.

Accordingly, the liquid crystal is aligned, and thus the liquid crystallayer 18 has transparency where no voltage is applied thereto.

Further, in this embodiment, between the liquid crystal display paneland a light source part 27, the polarization separating device 30 is notprovided, but a collimate lens (convex lens) 43 for making light fromthe light source part 27 a ray parallel to the first substrate 1 and thesecond substrate 2 of the liquid crystal display panel is provided heldin a panel holding frame 31 by a holding member 44.

In this liquid crystal display device, the overlap between the targetelectrode 5 and the counter electrode 21′ is a pixel part for displayinga target pattern. By applying voltage between the target electrode 5 andthe counter electrode 21′, the alignment property of the liquid crystallayer is disordered, so that the difference in refractive index betweenthe transparent solid substance and the liquid crystal molecule is usedto make the scattering state. Further, by turning off the voltage to thetarget electrode 5, the entire display area is turned into thetransmission state.

Employment of the above-described structure makes it possible to bringonly the part of the liquid crystal layer 18 corresponding to the targetelectrode 5 into the scattering state.

As shown in FIG. 10, among a subject incident light 51 and a subjectincident light 52 from below (lens side of) the first substrate 1, thesubject incident light 52 is scattered by the liquid crystal layer 18 onthe target electrode 5 and recognized as dark by the observer. Thesubject incident light 51 passes, as it is, through the liquid crystallayer 18 because it is substantially transparent, to be recognized asbright.

Accordingly, it becomes possible to display the target pattern dark in apicture of a bright subject. In this case, there is no layer forabsorbing light such as a polarizer in a direction of the subjectincident lights 51 and 52, and thus the observer can recognize thebright subject.

Next, operations when the light source part 27 is turned on areexplained.

In this embodiment, the polarization separating device is not providednear the liquid crystal display panel in order to simplify the structureof the liquid crystal display device. Thus, as shown in FIG. 10, thelight from the light source part 27 passes through the collimate lens 43to become a luminous flux parallel to the first and second substrates 1and 2 to enter the first substrate 1, the second substrate 2 and theliquid crystal layer 18 which constitute the liquid crystal displaypanel.

The incident light is repeatedly reflected due to the difference inrefractive index between the first substrate 1 or the second substrate2, and, the air layer, whereby the light can be made incident on theentire liquid crystal display panel.

The incident light 53 in FIG. 10 is illustrated representing lightcomponents which are incident directly on the liquid crystal layer 18.At the transparent part, the incident light 53 slightly goes out towardthe observer as a scattered light 56 due to slight scattering by theliquid crystal layer 18.

The liquid crystal layer 18 is scattered on the target electrode 5, andthus the scattered light 55 can be emitted in various directions towardthe observer as shown in FIG. 10.

The brightnesses of the target part in the scattering state and thebackground part in the transmission state when the light source part 27is turned on, which the observer recognizes, are explained using FIG. 8.The horizontal axis indicates the position in the display area of theliquid crystal display panel, and the vertical axis indicates thebrightness.

Since the polarization separating device is not provided between thelight source part 27 and the liquid crystal display panel in the secondembodiment, the background part where the liquid crystal layer 18 is inthe transparent state and the target part where it is not in thescattering state have a small scattering property to have a brightnessat a level L1 shown by broken lines 62 and 65.

At the target part where the liquid crystal layer 18 is in thescattering state, the brightness is at a high level Lm as shown by abroken line 66 because of its scattering property. Since the subject cannot be recognized at the background part which is brighter than thelight from the subject, it is preferable that the level L1 at thebackground part is as low as possible and the level Lm at the targetpart is moderately high.

Therefore, it is preferable to provide a light intensity change functionfor changing the intensity of light of the light source part 27 inaccordance with the environment where the liquid crystal display deviceis used.

In this second embodiment, it is attained by changing electric powerapplied to the light source part 27.

Next, the effectiveness of the invention is explained using FIG. 11.Incidentally, portions in FIG. 11 which is the same as those in FIG. 9are assigned the same numerals and symbols, in which the liquid crystalmolecule 80 and the transparent solid substance 84 shown in FIG. 9 arequoted. However, in the liquid crystal layer 18 of the secondembodiment, a part to which no voltage is applied is a transparent part18 a, and a part to which voltage is applied is a scattering part 18 b.

The liquid crystal layer 18 is composed of schematically bar-shapedliquid crystal molecules 80, and transparent solid substances 84 havinga schematically porous body made of an acrylic resin existing around theliquid crystal molecules 80. The liquid crystal molecule 80 has arefractive index ne corresponding to extraordinary light and arefractive index no corresponding to ordinary light.

The transparent state and the scattering state of the liquid crystallayer (mixed liquid crystal layer) 18 are generated by a differentialbetween a refractive index np of the solid substance 84 and therefractive index no or ne of the liquid crystal molecule, and alignmentproperties of the liquid crystal molecules (directions and ununiformityof the liquid crystal molecules).

In this embodiment, PNM-157 mixed liquid crystal manufactured byDainippon Ink and Chemicals, Inc. is used as a raw material of theliquid crystal layer, and further liquid crystal polymers are mixed inthe transparent solid substances. The gap between the first substrateand the second substrate of the liquid crystal display panel is filledwith the mixed liquid, crystal, and then the mixed liquid crystal isirradiated with ultraviolet light having a wavelength of 360 nanometers(nm) or longer for 60 seconds at a strength of 50 mW/cm² in a conditionwhere voltage is applied thereto to produce the liquid crystal layer.

As for the refractive indices of the liquid crystal layer 18, no=1.5 andne=1.7, and the refractive index np of the transparent solid substanceis about 1.5 (almost equal to no). Further, the liquid crystal molecule80 is aligned where no voltage is applied thereto. As for the directionsof the liquid crystal molecules 80 when the voltage is small, the liquidcrystal molecules 80 point in directions to have a small difference inrefractive index with respect to the transparent solid substances 84because of a large alignment compelling force by the liquid crystalpolymers, in other words, the long axes (refractive indexes ne) point ina direction from the first substrate to the second substrate. Since theincident light through the first substrate 1 is a circularly polarizedlight parallel to the direction of the refractive index no of the liquidcrystal molecule 80, the difference in refractive index at the interfacebetween the transparent solid substance 84 and the liquid crystalmolecule 80 is small, and thus the interface reflection is hardlygenerated, resulting in the transmission state. Therefore, the subjectincident light 51 passes therethrough with hardly scattered to be astrong outgoing light toward the observer.

Since a strong compelling force by an electric field is exerted on thedirections of the liquid crystal molecules 80 when the voltage is large,an alignment regulating force between the liquid crystal molecules 80and the liquid crystal polymers is defeated by the electric field.Therefore, the liquid crystal molecules 80 lose their alignmentproperties to point in various directions, which generates the interfacereflections between the refractive indices ne of the liquid crystalmolecules and the refractive indices np of the transparent solidsubstances to the incident light. Therefore, a plurality of microinterface reflections are generated between the liquid crystal molecules80 and the transparent solid substances 84, resulting in the scatteringstate. Accordingly, the subject incident light 52 is scattered to be aweak outgoing light toward the observer.

The emitted light 53 from the light source part 27 is a circularlypolarized light 75 with little polarization. The representativecomponents of the circularly polarized light is assumed to be an X-axisdirection polarized light component (first polarized light component) 76and a Y-axis direction polarized light component (second polarized lightcomponent) 77.

In the transparent part 18 a (the background part and the target part towhich no voltage is applied) of the liquid crystal layer 18, thedirections of the refractive indices ne of the liquid crystal molecules80 are aligned with a direction from the first substrate to the secondsubstrate by the liquid crystal polymers. Therefore, incidence of lighttilted, at the interfaces between the liquid crystal molecules 80 andthe transparent solid substances 84, from the directions of therefractive indices ne of the liquid crystal molecules 80 slightlygenerates reflections at the interfaces between the liquid crystalmolecules 80 and the transparent solid substances 84. As a result, thescattered light 56 is slightly generated and goes out toward theobserver.

In the scattering part 18 b corresponding to the target electrode 5 towhich voltage is applied, the directions of the refractive indices ne ofthe liquid crystal molecules 80 point in various directions because ofdecreases in the alignment properties of the liquid crystal molecules80. Therefore, the incident light is made incident in the directions ofthe refractive indices ne of the liquid crystal molecules 80, generatinga number of interface reflections between the liquid crystal molecules80 and the transparent solid substances 84, into a scattered state to bethe scattered light 55 and a strong outgoing light toward the observer.

This case is simple because only the light source part 27 is required toprovide around the liquid crystal display panel (the collimate lens 43is preferably provided but not essential). However, when the lightincident on the mixed liquid crystal layer 18 from the light source part27 is tilted from the mixed liquid crystal layer 18 toward the firstsubstrate 1 side or the second substrate 2 side, scattering occurs inthe transmission part (back ground part), which is a noise to thesubject incident light to decrease the visibility of the subject ascompared to the case where the polarization separating device isprovided. Therefore, it is preferable that the collimate lens 43 isprovided to make the light from the light source part 27 a collimatedluminous flux and to let it enter the liquid crystal display panel.

Further, in the second embodiment, the explanation is made using, as theliquid crystal layer 18, the liquid crystal layer (mixed liquid crystallayer) which is in the transparent state where no voltage is appliedthereto and becomes the scattering state by increasing the appliedvoltage. However, the same effect as that of this embodiment can beattained even if the polarization separating device is omitted in thefirst embodiment using the liquid crystal layer which becomes thescattering state where no voltage is applied thereto.

Third embodiment: FIG. 12 and FIG. 13

Next, the third embodiment of the liquid crystal display deviceaccording to the invention is explained with reference to FIG. 12 andFIG. 13.

FIG. 12 is a schematic cross-sectional view, similar to FIG. 7, of acamera module in which the liquid crystal display device is installed,in which the same portions as those in FIG. 7 are assigned the samenumerals and the explanation thereof is omitted.

The liquid crystal display device of the third embodiment has astructure almost in common with that of the liquid crystal displaydevice of the first embodiment.

The third embodiment is different from the first embodiment in that acold-cathode tube (fluorescent tube) is disposed as a light source part17, in place of the LED, to be parallel to one side surface of theliquid crystal display panel, a reflection type polarizer is used as apolarization separating device 30, and that a reflector 35 is providedaround the light source part 17.

The reflection type polarizer is a polarizer having as polarization axesa transmission axis and a reflection axis substantially perpendicular tothe transmission axis to reflect a light linearly polarized to thedirection of the reflection axis. As the reflection type polarizer, DBEF(trade name) manufactured by 3M Company is used.

A ray emitted from the light source part 17 is finally brought into alinearly polarized light by the polarization separating device 30 toenter the liquid crystal display panel.

By employing the above-described structure, the light from the lightsource part 17, as shown in FIG. 12, is made light whose polarization iscancelled by a diffuser 29 to enter the polarization separating device30 which is the reflection type polarizer. Then, the light becomes alinearly polarized light in the direction of the transmission axis ofthe reflection type polarizer to enter a first substrate 1, a secondsubstrate 2 and a liquid crystal layer 18 which constitute the liquidcrystal display panel.

Recognition of a subject by the incident light and incident light frombehind the first substrate 1, and display operations of a target patternare the same as in the case of the first embodiment, and thus theexplanation thereof is omitted.

Since the reflection type polarizer is employed as the polarizationseparating device 30 in the third embodiment, light passing through thereflection type polarizer is emitted as a linearly polarized light tothe liquid crystal display panel, whereas a component of light notpassing therethrough is reflected by the reflection type polarizer to bereturned to the diffuser 29, losing its polarization and being diffused,to return in a direction of the light source part 17. Since thereflector 35 is provided near the light source part 17, the light isreflected by the reflector 35 and passes again through the diffuser 29to reach the polarization separating device 30, and a part thereofpasses through the polarization separating device (reflection typepolarizer) 30 to be a linearly polarized light and goes out to theliquid crystal display panel.

In other words, absorption of light in the polarization separatingdevice 30 is little, which enables the light emitted from the lightsource part 17 to enter the liquid crystal display panel efficiently.

Further, on the outside surfaces of the first substrate 1 and the secondsubstrate 2 of the liquid crystal display panel, ultraviolet cuttinglayers 41 are provided respectively to prevent deterioration of theliquid crystal layer 18 due to a subject incident light from below (lensside of) the first substrate 1 and light from above (eyepiece side of)the second substrate 2 entering the liquid crystal layer 18.

Because irradiation of light having a wavelength shorter than 380nanometers (nm) generates a decrease in scattering property, a change involtage for causing a change into the transparent state, and yellowingin the liquid crystal layer 18, the provision of the ultraviolet cuttinglayers 41 is important to secure reliability.

Further, since the lens and the like are provided on the observer sideof the liquid crystal display panel, anti-reflection layers 40 areprovided under the above-described ultraviolet cutting layers 41respectively to prevent the outgoing light from the scattering part ofthe liquid crystal display panel from returning again to the liquidcrystal display panel by reflection by the lens and the like and beingreflected by the second substrate 2. This can further improverecognition of the subject incident light.

The anti-reflection layer 40 preferably decreases reflection within awavelength region from 380 nanometers (nm) to 800 nanometers (nm) whichis a wavelength range of the light emitted from the light source part17.

Furthermore, since the reflection type polarizer is used as thepolarization separating device 30, it is preferable to insert anabsorption type polarizer between the reflection type polarizer and theliquid crystal display panel in order to prevent a stray light of thesubject incident light from being reflected by the reflection typepolarizer while the light source part 17 is turned off.

In this case, the reflection type polarizer and the absorption typepolarizer are preferably set with directions of their transmission axesmatched, and actually the absorption type polarizer is bonded on thereflection type polarizer with an adhesive layer to constitute thepolarization separating device 30.

FIG. 13 is a view showing one example of means for automaticallycontrolling the intensity of light incident on the liquid crystaldisplay panel from the light source part 17 in accordance with theintensity of incident light from behind the liquid crystal displaypanel.

A polarizer 45 and a liquid crystal cell 46 are inserted between thelight source part 17 and the polarization separating device 30 toconstitute, together with the polarization separating device 30, aliquid crystal shutter, and a detection signal of an exposure meter 47is inputted into a liquid crystal driving circuit 48 for driving theliquid crystal cell.

The exposure meter 47 measures the intensity of incident light on thefirst substrate 1 side of the liquid crystal display panel and inputs asignal corresponding to the intensity of light into the liquid crystaldriving circuit 48. This causes the, liquid crystal driving circuit 48to change the voltage applied between opposed entire surface electrodesof the liquid crystal cell 46 in accordance with the intensity ofincident light. This changes optically rotating operations of a twistednematic liquid crystal layer filling the liquid crystal cell to changethe intensity of light passing through the polarizer 45 and thepolarization separating device 30.

Moreover, as for the light source parts provided in the liquid crystaldisplay device according to the invention, when the display area of theliquid crystal display panel is large, a plurality of the light sourceparts are provided therearound. Each emitted light is used to enableuniform illumination of the large area. Further, a plurality of lightsource parts for emitting light in different optical wavelength regionsare provided, or a plurality of light emitting elements for emittinglight in different optical wavelength regions are provided in one lightsource part, and they are selectively used, which also makes it possibleto select white illumination, red-green-blue illumination, or the like.

The optical wavelength used for illumination is preferably within arange from 380 nanometers (nm) to 800 nanometers (mn).

Moreover, as for the period during which the light source part is turnedon, the light source part is not preferably always turned on butselectively turned on by selection by the observer, in accordance withthe brightness of the environment where the liquid crystal displaydevice is used, or the strength of the subject incident light, andenabling the lighting period to be also selected. As a result, theelectric power consumed by the liquid crystal display panel can bedecreased to increase battery life, which results in a commercialproduct friendly to the earth's environment.

In the above-described embodiments, the liquid crystal layers of thefirst embodiment and the third embodiment are of a mode showing thescattering state while no voltage is applied thereto, and that of thesecond embodiment is of a mode showing the transparent state while novoltage is applied thereto. However, even if the liquid crystal layer ofthe mode showing the transparent state while no voltage is appliedthereto is used in the first embodiment and the third embodiment, thesame effects can be attained. Further, a dichroic dye may be mixed inthe liquid crystal layer to increase absorption characteristics.

Embodiment Installed in a Camera: FIG. 14 and FIG. 15

Hereinafter, the embodiment in which the camera module that is theliquid crystal display device according to the invention is installed ina finder optical system is explained with FIG. 14 and FIG. 15.

A camera module 10 that is the liquid crystal display device accordingto the invention is installed between a finder lens 104 and a finderscreen 106 in a camera body 101. A roof prism 102 is disposed on afinder eyepiece window lens 103 side of the finder lens 104, so that anobserver of the camera looks into from the finder eyepiece window lens103 to observe a subject.

On a photographing lens 100 side of the finder screen 106, there is amirror 105 to let a subject incident light 51 from the photographinglens 100 go out toward the finder screen 106. There are a shuttercurtain 107 and a film 108 on the opposite side to the photographinglens 100 with respect to the mirror 105. Further, at the lower side ofthe camera body 101, a battery 120 is provided to drive the liquidcrystal display panel and the like.

Further, as shown in FIG. 15, the camera body 101 has a shutter button112 for opening/closing the shutter curtain 107, and a power sourceswitch 113. Furthermore, this camera is of such a system that the film108 is loaded in a cartridge (patrone) 117 in the camera body 101, thecartridge 117 is held on a coupling shaft 115 for cartridge, and theother side of the film 108 is wound on a spool 118. Further, the camerahas a motor 116 for automatically adjusting a focus of the lens and thelike. Numeral 114 denotes a first circuit board, and numeral 119 denotesa second circuit board.

Connection between the position of the target pattern and the autofocusadjustment position of the camera is manually set by the observer bymeans of a focus setting dial 110 disposed around the power sourceswitch 113.

By employing the above-described structure of the camera, the visibilityof the target pattern can be improved even when the focus is adjusted ona part of the subject. Further, a display can be performed withoutdisposing a polarizer, which attenuates light of the subject incidentlight 51, between the photographing lens 100 and the finder eyepiecewindow lens 103, and thus the visibility of the subject can be improved.Furthermore, even when the subject incident light 51 is dim, thevisibility of the target pattern 5 can be improved by using the incidentlight from the light source part 27 disposed in the lateral direction ofthe liquid crystal display panel and the scattering property of theliquid crystal layer 18.

Moreover, as described above, the polarization separating device 30 isdisposed between the liquid crystal display panel and the light sourcepart (side light) 27 which are provided in the camera module 10, wherebythe incident light from the light source part 27 is reflected from thefirst substrate 1 side or the second substrate 2 side so that an areaother than the target pattern brightly shines by the light from thelight source part 27. In other words, noise to the subject incidentlight 51 can be extremely decreased. Further, since the polarizationseparating device 30 is in a film shape, the polarization separatingdevice 30 with a thickness of 200 micrometers (μm) or less issufficiently effective, thus the mounting volume can be extremelydecreased. In the case of camera, since optical components andelectronic components are arranged near the prism 102, space is limited.Further, they determine the design of the camera, and therefore it isvery effective that the mounting volume of the polarization separatingdevice 30 is small.

Industrial Applicability

As is clear from the above explanation, through use of the presentinvention, while the incident light from below the first substrate isbeing observed, when the environment where the liquid crystal displaydevice is used is dark, the incident light is weak, or the scatteringdisplay is hard to recognize, the outgoing light from the scatteringpart of the liquid crystal display panel is added, using the lightsource part provided around the liquid crystal display panel, to theincident light from below the first substrate to perform a display,whereby the visibility of the scattering display can be improved.

It is difficult for the observer to distinguish luminosity but theobserver has sensibility of color discrimination, and therefore whenstrong green light is incident from below the first substrate, red lightis made incident from the light source part to perform a display in redon the liquid crystal display panel, thereby improving the visibility ofthe display.

Further, the pixel part and the background part are provided, which arecomposed of the signal electrode and the counter electrode capable ofperforming a display in which almost the entire surface of the liquidcrystal layer used for the liquid crystal display panel is in thetransparent state. The pixel part and the background part are providedadjacent, which makes it possible to bring almost the entire surfaceinto the transparent display.

Further, the scattering type liquid crystal layer changeable between thetransmission state and the scattering state by voltage is employed forthe liquid crystal layer. Since the employment of the scattering typeliquid crystal layer enables a display without using a polarizer, thetransmittance of the liquid crystal display panel can be improved.

Therefore, the condition below the first substrate can reappear in apart other than the pixel part performing a display.

Further, the liquid crystal layer is a display body without lightemission, and thus when the external environment is dark, the pixel partdisplayed by the liquid crystal display panel becomes extremely hard torecognize.

Moreover, the light source part (side light) is disposed around theliquid crystal display panel to secure the visibility of the conditionbelow the first substrate, and further almost the entire liquid crystaldisplay panel other than the display pixel part is brought into thetransparent state, which makes it possible to introduce the light fromthe light source part to the entire display area through use of thereflection due to the difference in refractive index between the firstsubstrate and the air layer, and the reflection due to the difference inrefractive index between the second substrate and the air layer.

Further, since the transparent state and the scattering state arechanged by the differential in refractive index between the liquidcrystal molecule and the polymer, a weak scattering property isexhibited even in the transparent state depending on the direction ofthe liquid crystal molecule and the direction of the light from thelight source part. Therefore, in order to control the polarization oflight with respect to the direction of the liquid crystal molecule, thepolarization separating device is provided between the light source part(side light) and the liquid crystal display panel.

The polarization separating device can control the polarization of thelight source part by the absorption type polarizer having thetransmission axis and the absorption axis, the reflection-type polarizerhaving the transmission axis and the reflection axis, or a diffractiongrating.

Especially when the scattering property of the transparent part isdecreased, the transmission axis of the polarization separating deviceis disposed in the direction substantially perpendicular to thedirection of the refractive index of the liquid crystal that is adirection in which the difference between the refractive index of thepolymer and the refractive index of the liquid crystal is small, so thatthe polarized light passing through the polarization separating deviceis made incident only in a direction in which the difference inrefractive index between the polymer and the liquid crystal is small,thereby decreasing scattering. The liquid crystal shows the scatteringstate when voltage is not applied to the pixel part and becomestransparent state when voltage is applied thereto. During thetransparent state, the direction of no of the liquid crystal layer isparallel to the direction of the first substrate and the secondsubstrate.

For example, when a liquid crystal having a refractive index (no) in thedirection of ordinary light larger than a refractive index (ne) in thedirection of extraordinary light that is the opposite property of therefractive index explained with reference to FIG. 9 is used and apolymer (transparent solid substance) having no alignment property indirections of three dimensions is employed as the polymer, since therefractive index of the transparent solid substance is close to ne, thetransmission axis of the polarization separating device is disposed in adirection perpendicular to the direction of no. In other words, it ispreferable to arrange the direction of ne and the transmission axis ofthe polarization separating device in parallel.

Further, the intensity of light of the light source part which reachesthe liquid crystal display panel decreases in the case where thepolarization separating device is simply disposed between the liquidcrystal display panel and the light source part as compared to the casewhere the polarization separating device is not provided.

Therefore, the reflection type polarizer is used as the polarizationseparating device to emit a linearly polarized light, and the reflectedcomponent, its polarization being cancelled, is returned again to thereflection type polarizer, thereby improving the efficiency of emittinglight.

When the strength of the light incident from below the first substrateconstituting the liquid crystal display panel is low, the light of thelight source part (side light) provided around the liquid crystaldisplay panel is slightly reflected toward the observer from thetransparent part of the liquid crystal display panel to interfere thevisibility of the light going out from the first substrate, and thus thelight intensity change function is provided to decrease the brightnessof the light source part.

The light intensity change function employs one or both of means forchanging electric power supplied to the light source part and means forchanging light emission period.

Further, when the strength of the light incident from below the firstsubstrate constituting the liquid crystal display panel is low, thelight of the light source part (side light) provided around the liquidcrystal display panel is slightly reflected toward the observer from thetransparent part of the liquid crystal display panel to interfere thevisibility of the light going out from the first substrate, and thus thepolarization separating device is used to change the intensity of thelight incident on the liquid crystal display panel from the light sourcepart.

The transmission axis of the polarization separating device on theliquid crystal display panel side is fixed, and polarized lightseparating means and the polarization separating device are provided onthe light source part side. Since the application of voltage to thepolarized light separating means can control the polarizing property ofthe polarized light separating means, the intensity of light incident tothe liquid crystal display panel can be changed.

As the polarized light separating means, the liquid crystal displaypanel may be used, and the polarization separating device may be apolarizer.

In the above-described embodiments, the explanation is made using acamera as a device for which the liquid crystal display device is used,and the liquid crystal display device is naturally applicable to adevice for performing a display combining the incident light from belowthe first substrate and the incident light from the light source part.For example, that is a display device overlapped a front glass of a car,a timepiece for performing a time display on a picture, or the like.

1. A camera having a liquid crystal display device as a module which isinstalled in a finder optical system, wherein said liquid crystaldisplay device is composed of a liquid crystal display panel in which afirst substrate formed with a signal electrode and a second substrateformed with a single counter electrode on one surface, respectively, arecoupled together, with said signal electrode and said counter electrodeopposed each other, with a fixed gap provided therebetween byinterposing a sealing part at an outer peripheral part of a displayarea, and a liquid crystal layer is provided in the gap, wherein afinder screen is disposed outside said first substrate and a finder lensis disposed outside said second substrate of said liquid crystal displaypanel, said signal electrode is composed of a surrounding electrodeformed as a single body over almost the entire area of said displayarea, a pattern electrode isolatedly formed within said surroundingelectrode with a small gap therebetween, and a wiring electrode formedacross said surrounding electrode with a gap provided between saidwiring electrode and said surrounding electrode in order to selectivelyapply voltage to said pattern electrode, wherein said pattern electrodeis a target electrode for displaying a target pattern for autofocus,said counter electrode is provided over the entire area of said displayarea to face said signal electrode, said first substrate, said secondsubstrate, said signal electrode and said counter electrode are alltransparent, said liquid crystal layer is a scattering type liquidcrystal layer which changes in transmittance and scattering ratedepending on existence or absence of application of voltage by means ofsaid signal electrode and said counter electrode, in which scatteringdegree increases in a part to which voltage is not applied andtransparency increases in a part to which voltage is applied, said smallgap is made small in width so that scattering at said small gap isinconspicuous when most of display region becomes transparent byapplying voltage between said signal electrode and said counterelectrode and when said target pattern is displayed without applyingvoltage between said target electrode and said counter electrode, saidwiring electrode is made small in width so as to be inconspicuous whensaid target pattern is displayed without applying voltage between saidtarget electrode and said counter electrode, and a light source meanswhich emits linearly polarized light is disposed outside a peripheralpart of said liquid crystal display panel, and at least a part of saidsealing part facing said light source means has a light transmittingproperty to allow linearly polarized light emitted from said lightsource means to pass through said sealing part and enter said liquidcrystal layer.
 2. A camera having a liquid crystal display deviceaccording to claim 1, wherein said liquid crystal display panel, inwhich an outside of said second substrate is a visible side, alwayspresents a condition outside said first substrate to the visible side, aluminosity of a scattering part, where the transparency does notincrease, of said liquid crystal layer becomes higher than luminositiesof other parts while a light source part of said light source means isturned on, and the luminosity of said scattering part of said liquidcrystal layer becomes lower than the luminosities of the other partswhile said light source part is turned off.
 3. A camera having a liquidcrystal display device according to claim 1, wherein said light sourcemeans comprises a light source part and a polarization separating devicedisposed between the light source part and an outer peripheral part ofsaid liquid crystal display panel.
 4. A camera having a liquid crystaldisplay device according to claim 3, wherein an optical means composedof a convex lens is provided between said light source part of saidlight source means and said polarization separating device.
 5. A camerahaving a liquid crystal display device according to claim 3, whereinsaid scattering type liquid crystal layer of said liquid crystal displaypanel is a mixed liquid crystal layer composed of transparent solidsubstances and a liquid crystal, which is produced by applyingultraviolet light to liquid composed of liquid crystal and organicmonomers, and said polarization separating device is disposed so that atransmission axis thereof almost matches with a direction in which adifference between a refractive index of said transparent solidsubstance and a refractive index of said liquid crystal of said mixedliquid crystal layer is small.
 6. A camera having a liquid crystaldisplay device according to claim 5, wherein said polarizationseparating device is an absorption type polarizer having a transmissionaxis and an absorption axis substantially perpendicular to thetransmission axis.
 7. A camera having a liquid crystal display deviceaccording to claim 5, wherein said polarization separating device is areflection type polarizer having a transmission axis and a reflectionaxis substantially perpendicular to the transmission axis.
 8. A camerahaving a liquid crystal display device according to claim 7, wherein adiffuser is provided between said polarization separating device andsaid light source part, and a reflector is provided around said lightsource part.
 9. A camera having a liquid crystal display deviceaccording to claim 5, wherein said polarization separating device iscomposed of an absorption type polarizer having a transmission axis andan absorption axis substantially perpendicular to the transmission axis,and a reflection type polarizer having a transmission axis and areflection axis substantially perpendicular to the transmission axis,and said absorption type polarizer is disposed on said liquid crystaldisplay panel side and said reflection type polarizer is disposed onsaid light source part side respectively with directions of therespective transmission axes of said absorption type polarizer and saidreflection type polarizer matching with each other.
 10. A camera havinga liquid crystal display device according to claim 3, wherein lightintensity change means which controls increase and decrease of anintensity of light to make incident on said liquid crystal display panelin accordance with an intensity of light incident on said liquid crystaldisplay panel from outside said first substrate is provided in saidlight source means.
 11. A camera having a liquid crystal display deviceaccording to claim 10, wherein said light intensity change meanscomprises a liquid crystal cell provided between said polarizationseparating device and the light source part, a polarizer arranged on alight source part side of the liquid crystal cell, an exposure meter fordetecting the intensity of the light incident from outside said firstsubstrate, and a liquid crystal driving circuit for changing voltageapplied to said liquid crystal cell in accordance with an output fromsaid exposure meter.
 12. A camera having a liquid crystal display deviceaccording to claim 5, wherein an ultraviolet cutting layer is providedat least on one of outer surfaces of said first and second substrates ofsaid liquid crystal display panel.
 13. A camera having a liquid crystaldisplay device according to claim 5, wherein an anti-reflection layerfor preventing reflection of light within a wavelength range of lightemitted by said light source part is provided at least on one of outersurfaces of said first and second substrates of said liquid crystaldisplay panel.
 14. A camera having a liquid crystal display deviceaccording to claim 3, wherein said light source part comprises aplurality of light emitting elements which can selectively emit lightsin different optical wavelength regions.
 15. A camera having a liquidcrystal display device according to claim 3, wherein said light sourcepart can selectively emit light in different optical wavelength regionsin accordance with brightness of environments or strength of incominglight, and the period in which said light source part is turned on canbe selected.
 16. A camera having a liquid crystal display deviceaccording to claim 1, wherein said liquid crystal display device is amodule comprising a panel holding frame and a panel fixing frame,installed in a finder optical system of a camera, and a gap between saidpanel holding frame, said panel fixing frame, and said liquid crystaldisplay panel installed in said frames is filled with a heat insulatingseal.
 17. A camera having a liquid crystal display device according toclaim 1, wherein a width of said small gap and a width of said wiringelectrode is about 3 μm respectively.
 18. A camera having a liquidcrystal display device according to claim 3, wherein said light sourcepart is composed of a light emitting diode for emitting red light.